


A Costly Mistake

by thewinchesterlifestyle



Category: Supernatural
Genre: Bottom Dean, Breeding, Come Inflation, Creature Castiel, Double Anal Penetration, Double Oral Penetration, Double Penetration, Eggpreg, M/M, Mating Cycles/In Heat, Octo Castiel, Omega Dean, Rough Sex, Size Kink, Tentacle Rape, Tentacle Sex, Tentacles, Top Castiel, Twink Dean, dubcon, face fucking
Language: English
Status: Completed
Published: 2016-07-23
Updated: 2016-07-23
Packaged: 2018-07-26 03:35:01
Rating: Not Rated
Warnings: Rape/Non-Con
Chapters: 1
Words: 1,738
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7558546
Author URL: https://archiveofourown.org/users/thewinchesterlifestyle/pseuds/thewinchesterlifestyle
Summary: <blockquote class="userstuff">
              <p>Dean was swimming out from the shoreline when he noticed a beautiful face under the water. Thinking the person is drowning he dives underwater but by the time he realizes what it is underneath the water it's too late.</p>
            </blockquote>





	A Costly Mistake

**Author's Note:**

> Written for a prompt.

Dean sighed out as he floated in the water and enjoyed the weightless feeling. He knew he had to enjoy it since his Heat was coming soon and he’d have to lock himself up once more to ride it out. He’d have to lock himself up and fuck back onto a fake knot that would do nothing for him in the long run.

It wouldn’t provide relief and it wouldn’t be what he needed. He shifted in the water and started to swim once more until he noticed something under the water. The features were handsome with piercing blue eyes and dark hair shifted in the moving water. Worry and fear climbed up his throat when he realized someone was possibly drowning.

Without thought or concern for himself he dove down into the clear water towards the man below. His arms and legs propelled him closer but that was when he noticed something. He was only feet away from what he thought was a drowning man when he saw it wasn’t a man. Dark tentacles moved through the water and lashed out at him to drag him close. Dean jerked and struggled as his lungs started to burn. The creature seemed to sense something and Dean felt himself being pulled towards the surface. He greedily took in lungful’s of air and tried once more to twist himself from the creature.

Tentacles kept him bound thoroughly and it was impossible to break the tight hold they had on him.

They moved through the water as Dean thrashed and snarled against the tentacles holding him tightly. He could feel his swimming trunks being removed and thrashed again. “Let me go!” it was growled out but the creature didn’t seem to care about his anger. Instead it removed them and teased at Dean’s body. “Hey none of that.” Dean yelped when his legs were spread open in the water and a tentacle pressed against his hole. 

A coo escaped and Dean gasped as another tentacle stroked along his cock and balls. Dean barely registered when they had moved into a cove and he was being spread out in the air for the octoman to take in his bare body. The tentacles held him spread open, legs almost in a split and exposed him to hungry eyes as he was turned in the air.

The creature’s fingers reached out to touch him and moved over warm skin as Dean shook. A few seconds passed before a tentacle moved back to tease at his hole and one of those hands reached down to weigh his balls. Fingers touched them and teased as Dean couldn’t hold back a small moan.

His hole was starting to leak slick and he whined at his body betraying him.

Tentacles continued to trace over his body, learning it, as the tentacle at his hole started to work itself inside him. The ones around his legs pulled him open wider into a split that ached and Dean’s mouth dropped open at the feeling of being filled up. The sensation had him gasping in a combination of pain and low burning pleasure. The tentacle stroked his prostate and insides before pushing deeper. “Oh…hey this-” a strangled moan escaped and his mouth dropped open.

Without prep the thick tentacle inside him, that only got thicker the further it went inside, burned and ached horribly.

Dean’s eyes clenched shut as he moaned and struggled slightly in the tentacles that were acting as bindings. One moved up his body until it reached his mouth and pushed inside. Dean’s eyes flew open at that as he was filled at both ends. His throat bulged as it pushed inside and tears gathered in his eyes at the decrease in air. He forced his mind to calm and focused on breathing through his nose as the creature pushed further inside.

Slick was leaking around the tentacle fucking his ass and his body shook at the sensation. Dean twisted as his body started to heat up with the arousal the creature was causing. Tentacles were fucking into him at both ends and it was getting harder to focus on anything but how it felt and how his body ached uncomfortably.

He was getting lost in how it felt to be so full and thoroughly used as though he was nothing more than two holes. He’d been told for years that this was what his body was made for and now something was finally doing exactly that.

Using him.

Another tentacle nudged up against the one working inside his ass and Dean moaned around the one fucking his mouth. It wriggled and shifted as it started to slowly push inside. The tentacle fucked up in short little thrusts as his body opened up for the girth of two to fuck up into his ass.

His hole was stretched taunt around the two tentacles as they worked together to pound up into him, pushing further and further inside him, as he hung there. He felt another one, similar to the smaller one using his mouth, moving up to join the one fucking his face. It pushed inside and suddenly he was full of tentacles. They fucked into him roughly and his body opened up for it.

Dean’s belly bulged as they pushed in deeper.

The tentacles fucking up into him were pressing against his belly and the creature could see itself filling Dean up.

When it shifted him Dean could see the creature better. Blue eyes were dark, its full mouth dropped open as it panted and the creature’s cheeks were flushed with arousal. The four tentacles writhed inside him, pumping in and out quickly, as Dean choked and whimpered. Slick ran down the two tentacles working Dean’s ass over and the two in his mouth had his throat bulging.

The creature kept him spread wide with his tentacles as he touched and clearly enjoyed the sensation of his tentacles moving inside the tight heat. “ _Mine_.” was snarled out and Dean’s whole body felt hot. His orgasm was building until it had him clenching down tightly around the tentacles fucking him.

He went limp in the creature’s hold as it kept using his holes with enthusiasm. Dean barely registered the warmth pouring down his throat as the tentacles there emptied inside him and then the ones in his ass were shooting hot liquid inside him.

Dean struggled weakly as he was completely filled up and his belly started to bulge as the tentacles emptied themselves. He moaned and shifted in the hold as the ones in his mouth removed themselves. They stroked down his cheeks and down his body as he hung there limply. He felt heavy and bloated where copious amounts of the creature’s come continued to spill into him, filling him unnaturally full.

The creature was far from done with him and he was far too oversensitized to do much more than moan weakly. His muscles were lax and he glanced down to see his stomach rounded from the creature’s seed. “ _Oh_.” his toes curled at the sensation of one of the tentacles buried in his ass moving back out while the other pushed even deeper to keep him plugged.

Fingers stroked over the bulge of his belly and the creature’s hands dug in to his skin. “Mine. My Omega.” the voice was rough and Dean struggled in the hold. He could smell the creature’s arousal and moaned as his body reacted to the scent instinctively. Dean felt himself being dragged closer and a warm face pressing against the juncture of his neck and shoulder. Hot breath huffed out and Dean felt lips there as the tentacle inside him twisted around.

They were moving once more as Dean lay nestled in the tentacles holding onto him tightly. The octoman moved them through the cove and suddenly they were going under the water once more. Dean glanced around under the water and shook in the creature’s hold as it held him close. Finally they broke through to air and he struggled to get air once more as he was dragged further into the cave as they moved through the water. The tentacle inside him pulled out and Dean gasped at the sudden feeling of no longer being stuffed completely full.

Come and slick gushed out of his gaping hole once there was nothing to hold it inside him any longer.

His eyes drooped and Dean found himself slipping into unconsciousness as his body sought to rest after being so thoroughly used for the first time. What Dean didn’t know was that the creature had no intentions of ever letting him go and it hadn’t taken him long to realized that he was essentially a breathing fucktoy for the creature.

It was constantly spreading him open with tentacles and fucking him full until his belly bulged with come. While he lay there trying to recover from being used Castiel, a name he’d learned on the fourth day, would go hunt for food and no matter how much he wanted to escape he was never able to move very far after it had used him.

The creature would hold him close when it slept, a tentacle sometimes keeping its come inside Dean, as he lay in its hold. When Dean’s Heat finally came the creature had released happy coos and words of excitement at the way Dean was  _begging_  to be filled up. His Heat had been a blur of tentacles and being fucked full until he’d get a brief break to take care of himself.

On the fifth day of his Heat something changed. One of the tentacles buried inside his ass shifted and Dean could feel it push into his womb, past the barrier, before it started to push large eggs up inside him.

They burned violently as they pushed past his abused rim, moving up inside him and finally being pushed into his womb. Each egg had him feeling heavier and heavier as he sagged in the creature’s hold, legs spread wide.

This time when it finished inside him, ten eggs filling his womb along with the creature’s release, his belly remained large and swollen long after the copious amounts of its come had leaked back out of his gaping hole.

He blinked, body aching and muscles shaking, as the creature cooed at the swell of his stomach and the pleased air of successfully impregnating him.


End file.
